The present invention relates to a select system for an automatic transmission.
The present application claims priority from Japanese Patent Application No. 2002-189359, the disclosure of which is incorporated herein by reference.
FIG. 7 and FIG. 8 illustrate a known select system 1 for the automatic transmission. A select lever 2 is shifted to the left and right for switching over between an automatic transmission mode (hereinafter referred to as “A/T mode”) 3 and a manual transmission mode (hereinafter referred to as “manual mode”) 4. Generally, when the select lever 2 is in the A/T mode 3, a linkage member 5 which is operatively connected to the select lever 2 extends and retracts a selector cable (not shown) which is connected to an inhibitor (range) switch of the automatic transmission (not shown), via an end member 6, whereby an automatic transmission control is achieved. For the manual transmission control of the automatic transmission, the select lever 2 is first shifted in the D range position of the A/T mode 3 and then to the right as shown in FIG. 7 into the manual mode 4. A forward or backward shift of the lever in this mode turns on a switch 8 in an upper case 7 either to shift up or to shift down.
The select system 1 includes the following structure so that the linkage member 5 is maintained in the D range position while allowing the select lever 2 to be shifted in the manual mode 4, after switching over the select lever 2 from the A/T mode 3 to the manual mode 4.
The select lever 2 is integrally formed with a rod 9 which is tapered as shown in a side cross section and protrudes from one side face of the lever 2 toward the other side as shown in FIGS. 7 and 8. The linkage member 5 includes a guide groove 10 having a shape bulged in the middle as shown in the side cross section in a corresponding position to receive the rod 9. When the select lever 2 is in the A/T mode 3, the rod 9 fits into a tapered rod receiving hole 11 opened at the top in the center of the guide groove 10 so that the linkage member 5 is rotated with the lever shift. When the select lever 2 is switched over from the A/T mode 3 to the manual mode 4, the rod 9 is retracted into an elongated groove 12 which opens to the front and back continuously with the lower end of the rod receiving hole 11, thus being freed from the engagement. In this state; the linkage member 5 is not rotated when the select lever 2 is moved.
In the select system 1, the rod 9 of the select lever 2 is tapered for an easy engagement and is removal from the rod receiving hole 11 of the guide groove 10 opened in the linkage member 5. One problem with such a system was that the rod 9 of the select lever 2 sometimes disengages from the rod receiving hole 11 of the linkage member 5 due to external factors such as vibrations while running on a dirt course or a gravel road, leading to an unexpected shift change from the A/T mode 3 to the manual mode 4.
Moreover, because the linkage member 5 is released from the select lever 2 in the manual mode 4 and not inhibited from rotating, it could accidentally be rotated due to the aforementioned external factors. A rotation of the linkage member 5 leads to a forcible shift change of the automatic transmission even when the select lever 2 is in the manual mode 4; thus an accidental release of the select lever 2 from the gear position or an unexpected gear change could occur during the drive in the manual mode.